A tiny piece of metal which gave vital clues to the true location of the Battle of Bosworth has been declared treasure by a coroner.

The silver boar badge was dropped in the mud more than 500 years ago by a knight who fought alongside King Richard III, historians believe.

The white boar was the king's personal emblem and silver gilt boars were made for his knights and nobles.

The emblem will be independently valued by a committee of experts.